Facebook Instagram

Blood/Breath Alcohol Content

This calculator is designed to estimate your blood/breath alcohol concentration. Its primary purpose is to provide useful information about the responsible use of alcohol.

Blood/Breath Alcohol Concentration (BAC) is the amount of alcohol in the bloodstream or on one's breath. BAC is expressed as the weight of ethanol, measured in grams, in 100 milliliters of blood, or 210 liters of breath. BAC can be measured by breath, blood, or urine tests.

In the United States, the legal limit is 0.08 percent. If your blood has more than 0.08 percent alcohol concentration, you’re legally intoxicated. However, concentrations of 0.05 percent or lower can affect your ability to safely drive a vehicle.

INSTRUCTIONS: Select weight, drinks consumed, time period and gender. Then click the “compute your BAC” button.

Weight: (pounds)
Drinks consumed: (12 oz. beer or equivalent)
Over time period: (hours)

Your BAC will be:

The results from this calculator are ESTIMATES. Several things can affect your BAC including:

  • How much alcohol you drink.
  • How fast you drink. In general, the quicker you drink, the higher your peak BAC will be.
  • Body size. Large people tend to reach lower BACs than smaller people, given the same amount of alcohol.
  • Food in your stomach. When there is food in your stomach, alcohol is absorbed more slowly into the bloodstream. The BAC rises more rapidly when you drink on an empty stomach because there is no food to dilute the alcohol.
  • Type of mixer used. Water and fruit juices mixed with alcohol may slow the absorption process, while carbonated beverages may speed it up.
  • Gender differences. Women reach higher BACs faster because they have less water in their bodies and more adipose tissue (fat), which is not easily penetrated by alcohol. A man and a woman, with all other factors being equal, both drinking the same amount of alcohol, will have different BAC levels. Hers will be higher.


Your actual BAC is dependent on many complex factors, including your emotional and physical condition and health, and what you've recently ingested (including food, water, medications and other drugs). No blood/breath alcohol calculator is 100% accurate. The best that can be done is a rough estimation of your BAC level. You should not consider this a guideline for how much you can drink and still drive responsibly, or avoid being arrested! The best policy is don't drink and drive. Period.

NOTE: The basic formula for estimating a person's blood/breath alcohol concentration comes from the National Highway Traffic Safety Administration.

This calculator was provided by the Wisconsin Department of Transportation Safety and Consumer Protection website.

Click Here to return to Fitness Calculators Main Page.